“Some 22 people involved in the attack in Ahvaz have been identified and arrested … weapons, exclusive material and communication equipment were seized in the house that belonged to the five-member terrorist group that carried out the attack,” a ministry statement said, according to the semi-official Tasnim news agency.

Gunmen fired on a viewing stand where Iranian officials had gathered on Saturday to watch an annual parade marking the start of Iran’s 1980-88 war with Iraq. Twelve members of Iran’s elite Islamic Revolutionary Guard Corps were among the 25 dead.